Oh it's definitely part learned and part genetic. I've always had a strange reaction to cilantro. As soon as I bite into fresh cilantro, it's as though this toxic gas fills my mouth. Another friend of mine has the same issue. One day I read that cilantro is an item that some types of people are genetically predisposed to taste differently. Weird, huh?
When I met DH, he was very picky about food, but he came from a very limited societal experience. Moving to a larger city, meeting new people and believe it or not, traveling for business has really made him more willing...actually, excited...to try new things. What we've figured out, though, is that what he's had issues with in the past and still struggles with are long-term, deep-seated perception and TEXTURE. I've seen him eat something before and say, "This actually tastes really good, but I'm having a hard time with it" b/c his past childhood food prejudices are still fighting with his brain saying "ewww, gross!!!", or the texture is freaking him out. Like onions -- he will tell you he doesn't like onions. But I've actually fed him onions lots of times, just camo'd them. As long as he doesn't know he's eating it, the taste doesn't bother him. He also won't drink milk on the expiration date even if I taste it and tell him it's fine. I always joke with him that there is not a chip in the milk that causes it to self-destruct on the expiration date, but he simply can't get past it.
Personally, I have some of the same issues with some sushi. I can eat the rolls, but I can't do nigiri or sashimi. My mind just freaks out. Although, oddly enough, I love beef carpaccio and my steaks rare. And I can't eat warm fruit. We all have our weird things.